Containers used to preserve foods and other perishable goods are particularly dependent on the seal integrity of the container. Such containers employ a variety of sealing mechanisms including threaded lids, frictionally interfacing tops which deflect or “snap” into place, mating tongue and groove strips or the like. In those containers using threaded tops, the seal integrity is dependent on the tolerance of the threads as well as the torque applied to the lid when closing. With lids which snap into place, the seal integrity is again dependent on the tolerances under which the lid and container rims are manufactured, as well as the material from which they are made, and the degree of deflection needed to secure the lid into a closed position.
Customer satisfaction naturally involves an adequate seal, but also the ease with which the customer can use the container. If the container requires a high rotational or lateral force to open or close, then the customer may become frustrated even when the seal is effective. Additionally, the method by which various customers grasp and otherwise handle the container includes an array of various dynamics. Such dynamics may include whether the customer is right handed, left handed, the strength, age, and dexterity of the user, and how they choose to grasp the container cover.
Force analysis of container caps, particularly in the pharmaceutical industry, is known in order to verify that proper sealing forces are applied to a medicine cap during the manufacturing process and to ensure proper levels of force are required to open the container if the bottle is to be resistant to child opening or the like. However, during seal testing the container body is surrounded by various invasive clamps and fixtures to keep it immobile during force analysis of the cap removal. Such a configuration prevents a force analysis representative of a human hand while opening or closing the cap in a more “natural” manner. Alternatively, the obstructive mounting hardware may be eliminated by bolting the container to the platform, however, this requires piercing the container and thus has uncertain results on the structural integrity of the container.
It would, therefore, be advantageous to analyze various dynamic multi-axis forces applied to a container during the process of opening or closing its cover, in which the container is not obscured by fixturing hardware or damaged by an invasive fixturing process.